The lines |/\ are tied to the unmovable nodes Oo.(As you see, four lines come out of O and one out of o.) X denotes a crossing, which is like a virtual crossingfrom knot theory, i.e. you can move it ad lib and anyline over any other. Should they cross in the process,well duh, then you have more crossings.)

Can you move the lines around such that no horizontalline going through this graph cuts more than threeof these lines? I think no, but can you lend me aformal proof? -- Hauke Reddmann <:-EX8 fc3a501@uni-hamburg.deDie Weltformel: IQ+dB=const.